Breast MRI with dynamic contrast-enhanced series (DCE MRI) is sensitive for breast cancer diagnosis (sensitivity 95-100%) with variable specificity (37-97%). Breast MRI was also used for pre-operative staging, and monitoring of therapeutic response of neoadjuvant chemotherapy (NAC). DCE MRI analysis with semi-quantitative and pharmacokinetic method can discriminate the responders versus non-responders during NAC. Analysis of choline peak on proton MR spectroscopy (MRS) can increase the MRI specificity of breast lesion diagnosis to 82-100%. Choline analysis was also used for monitoring treatment response of NAC. The change of choline integral can parallel the response status of NAC and was well correlated (r=0.91; P=0.01) with the change of lesion size, and the choline change can be found as early as 24 hours after first dose of chemotherapy.